With mine i'm not taking any green off but the yellow dead leaves near the bottom of the plant but it just means the buds will be the thing the plants focused on, not healing itself.
Depends on the pheno. I grew multiple la divas and one had to be trimmed because it was blocking so much light that the owner growth wouldnt get dark green.
Marijuana eats up sun rays like tomato plants. Ask anyone with any experience with a real tight canopy if the lower growth doesn't lighten. I've seen it on my auto. I didn't train her and she grew a thick canopy. I believe outdoor growers could weigh in here as well.
Where do people come up with stuff like this??? This is a plant, just like any other plant; it's botany. Do your research instead of saying what someone said in a forum.